The present invention relates to an apparatus for the lateral straightening or alignment of sheet material located on a conveyor, particularly for straightening a scale or flake flow or stream of printing products, as well as a method for operating the same.
The two-sided arrangement of metal members on a conveyor belt is known, whereby they are moved by a crank gear in such a way that they move together or straighten from the side to form the individual sheets of the scale or flake stream, i.e. the scale or flake stream elements, into a uniform stream.
In the case of the aforementioned apparatus with preferably metal guide members on either side of a conveyor belt and reciprocatable at right angles to the conveying direction of the printing product, there is supposed to be a reduction to the undesired braking or friction action occurring between the running scale stream and the stationary guide members during the conveying process compared with the previously known stationary guide members, i.e. those which are laterally fixed to a conveyor belt. This friction action through the printing product which abuts against the guide members and slides along the same is greatly dependent on the order of the scale stream. In extreme cases, there can be an uninterrupted braking action, leading to a greatly increased risk of disordered moving together of the scale stream and a resulting blocking of the printing product delivery. This danger is adequately counteracted by the aforementioned apparatus, in which the guide members are moved away from and then back towards the scale stream. In the case of this known apparatus, an uninterrupted braking action leading to accumulations or congestion need no longer be feared, but such accumulations can still occur with highly disordered scale streams or flows due to "collisions" of individual printing products.
Due to the greatly increased output of printing products as a result of the further development of printing presses, a need has arisen for a rapid, but trouble-free conveying of the printed sheet material from the printing presses to further processing means. Thus, the delivery speed of the printing product must be increased, so that inter alia new conveying problems occur in connection with the straightening of the scale flow as a result of the increased braking or friction action of the printing product coming into contact with the guidance means. In the case of high speed processes, such as are under discussion here, even minor faults lead to production stoppages which sometimes lead to high material losses.